In many applications, it is desirable to attach an abrasive roll to a rotatable output shaft, so that the abrasive roll may be rotated and contacted with a workpiece to abrade material from the workpiece. The abrasive roll is typically cylindrical, and has a cylindrical central bore through which the shaft is fitted. The outer surface of the cylindrical roll includes an abrasive coating, which may be, for example, a bonded or coated abrasive.
In some instances, the shaft onto which the abrasive roll must be mounted is permanently mounted to a machine at each end of the shaft. That is, the abrasive roll may not be mounted on the shaft, because each end of the shaft is attached to a machine, or is otherwise inaccessible. Furthermore, unitary cylindrical abrasive rolls may be difficult to remove from a shaft, due to friction between the shaft and the roll, contaminants on the shaft, and the like. In these situations, a split abrasive roll is used instead of a unitary abrasive roll.
The split abrasive roll is, in essence, a unitary abrasive roll that has been divided along its length to provide two or more components that cooperatively form a complete abrasive roll. For example, FIG. 1 illustrates an abrasive roll 1 having opposed, semicylindrical abrasive roll members 3 adapted for affixation to a cylindrical, rotatable shaft 2. Abrasive roll members 3 are typically attached to shaft 2 using bolts 4 at each end of the roll members, which bolt passes through shaft 2 at two points, as shown in FIG. 1. Japanese Utility Model Publication No. 61-7893 has discloses a similar method of fixing abrasive roll members to a rotary shaft. The two roll members 3 each include an abrasive outer surface 3a, against which a workpiece may be applied when the shaft and abrasive roll are rotated.
Although the method for fixing a split abrasive roll described above is satisfactory for some applications, certain disadvantages are also evident. For example, the centrifugal force exerted on the abrasive roll members during rotation of the shaft tend to cause flexing, or bowing, in the center portion of each roll member. Such bowing is undesirable because the surface finish imparted by a bowed roll member is not uniform. The center portion of the roll member, because it extends to a greater radial distance than either of the ends portions, tends to abrade more material from the workpiece, which may be unacceptable. Furthermore, the flexing of the abrasive roll members tends to produce extra noise, which can be distracting. Although a reduction in the rotational velocity of the abrasive roll may attenuate the effects described above, the productivity of the abrading apparatus is similarly reduced.
One method of reducing or preventing the flexing problem and noise problem described above is to provide a third bolt to affix the center of the abrasive roll members to the shaft, as shown in FIG. 2. A hole 5 may be formed through each roll member and through shaft 2, and a third bolt 4 may be used to affix roll members 3 to shaft 2. This construction prevents the roll members 3 from radially flexing in the center portion thereof, even in response to the centrifugal force applied during rotation. However, other problems may instead result.
The formation of holes 5 through abrasive surfaces 3a of each of the roll members 3 may cause the workpiece to be abraded nonuniformly. The holes 5, because they do not present an abrasive surface for contact with the workpiece, result in less abrading in the areas of the workpiece proximate the holes. Furthermore, abraded material may accumulate in holes 5, which may also be unacceptable.
In view of the deficiencies of the prior art, it is desirable to provide a split abrasive roll that can be readily mounted on and removed from a rotatable shaft, reduce or prevent radial flexing of the center portions of the roll members, reduce excess noise production during operation, and provide a uniform surface finish to a workpiece.